Turbine blade with moving heel

Abstract

Blade (30) having at its distal end a heel (34) comprising a first lateral edge (40) and a second lateral edge (50) each comprising a bearing surface (44, 54) and a male or female retention member (42, 52), the first lateral edge (40) and the second lateral edge (50) of two adjacent blades are configured to maintain contact between their respective bearing surfaces (44, 54) when two adjacent blades move relative to each other between a close relative position and a distant relative position in which the distance between the two adjacent blades is comparatively greater than in the close relative position, and in which the first retention member (42) and the second retention member (52) of adjacent blades are provided to come into contact in the distant relative position so as to prevent the blades from moving apart greater than the distance in the distant position. Figure for the abstract: Fig. 3

Description

Title of the invention: Turbomachine blade with moving heel Technical field

[0001] The present disclosure relates to a turbomachine blade. The present disclosure also relates to an assembly of two blades, a moving wheel comprising the blade, a method of assembling a moving wheel, and a turbomachine comprising the moving wheel. Prior art

[0002] Turbomachine blades typically have a heel having a so-called "Z" shape, that is to say comprising a male part having a substantially chevron shape with a flat and a corresponding female part, so as to circumferentially hold the blades in position relative to each other by inserting the male parts into the corresponding female parts.

[0003] The proper functioning of a moving wheel comprising such blades involves maintaining a certain level of mechanical clearance between the blades, so as to leave space for thermal expansion of the parts in operation.

[0004] However, due to the mounting of the circumferentially adjacent blades at their respective heels, an accumulation of clearances all around the moving wheel results in a spacing which is comparatively greater at a position of the moving wheel where the mounting of two blades is imperfect, or even faulty. Due to the forces caused by contact with abradable elements of the stator, this spacing tends to increase until it causes one blade to become dislocated from the other circumferentially adjacent blade.

[0005] Such blade dislocation can lead to a reduction in the thermomechanical performance of the moving wheel, or even a risk of unforeseen contact and damage or breakage of the blade, which can lead to a shutdown and damage to the turbomachine.

[0006] There is therefore a need to design a blade at least partially free from the aforementioned drawbacks. Statement of the invention

[0007] To this end, the present invention relates to a turbomachine blade intended to be mounted around a main axis of rotation of the turbomachine and having at its distal end a heel comprising a first circumferential end edge and a second circumferential end edge respectively configured to cooperate by complementarity of shape with the second circumferential end edge and the first circumferential end edge of the heel of another circumferential blade. conferentially adjacent and identical to said blade, in which the first circumferential end edge comprises a first bearing surface and a first retention member, the second circumferential end edge comprises a second bearing surface and a second retention member, the first retention member and the second retention member respectively comprising a complementary male retention member and a complementary female retention member, the first circumferential end edge of said blade and the second circumferential end edge of the other circumferentially adjacent blade being configured to define a translational sliding contact between the first and second bearing surfaces when said circumferentially adjacent blades move relative to each other between a close relative position and a far relative position, and wherein the first retaining member of said blade and the second retaining member of the other circumferentially adjacent blade are configured to be spaced apart in the close relative position and to come into contact in the far relative position.

[0008] Typically, the translational sliding contact may take place between the respective first and second bearing surfaces of said blade and said circumferentially adjacent blade.

[0009] Typically, the first retaining member of said blade and the second retaining member of the other circumferentially adjacent blade in the remote relative position are configured to come into contact in the remote relative position so as to prevent, in the remote relative position, a relative separation of the blades.

[0010] The upstream and downstream directions are defined relative to the overall direction of circulation of the fluid in the turbomachine when the blade is mounted in the turbomachine.

[0011] By "fluid" is meant the fluid with which the blades are intended to react, typically air or exhaust gases at various temperature and pressure levels depending on the stage in which the blades are intended.

[0012] Typically, the overall direction of circulation of the fluid in the turbomachine is parallel to the main axis of the turbomachine.

[0013] Typically, the main axis of the turbomachine is coincident with the axis of rotation of the turbomachine blade.

[0014] In the present disclosure, the main axis or main axis of rotation of the turbomachine is the axis of rotation of the blade when the blade is mounted in the turbomachine. The axial direction corresponds to the direction of the axis of rotation of the blade.and a radial direction is a direction perpendicular to the axis of rotation of the blade and intersecting this axis. Similarly, an axial plane is a plane containing the axis of rotation of the blade and a radial plane is a plane perpendicular to this axis. A circumference is understood as a circle belonging to a radial plane and whose center belongs to the axis of rotation of the blade. A tangential or circumferential direction is a direction tangent to a circumference; it is perpendicular to the axis of rotation of the blade but does not pass through this axis. A tangential or circumferential plane is a plane strictly parallel to the axis of rotation of the blade, that is to say not intersecting this axis and not including this axis. An axial or radial section corresponds respectively to a section along an axial plane or along a radial plane.Hereinafter, a substantially radial plane or a substantially circumferential plane will be referred to respectively as a plane slightly inclined relative to a radial plane or a circumferential plane. The terms "inner" and "outer" and their derivatives are defined relative to the main axis.

[0015] Such a structure has the double advantage of allowing a certain latitude of movement between two circumferentially adjacent blades, while preventing the disengagement of these blades.

[0016] In particular, such a structure allows the parts to expand freely during operation and to allow small amplitude movements.

[0017] The assembly of the mobile wheel is then made easier, and the risks of damage during operation are reduced.

[0018] Typically, the first retaining member and the second retaining member of the circumferentially adjacent blades are configured to only contact in the remote relative position.

[0019] Typically, the transition from the near relative position to the far relative position is achieved by circumferential relative displacement of the heels around the main axis, or in a circumferential plane, in particular a substantially circumferential plane. For example, the transition from the near relative position to the far relative position is achieved by displacement of the heels in the plane of the blade platforms.

[0020] Typically, the first bearing surface comprises a cavity capable of receiving the second retention member.

[0021] Typically, at least one of the first retention member and the second retention member has a triangular or rectangular shape.

[0022] For example, the first retention member and the second retention member have a triangular shape. For example, the first retention member and the second retention member have a rectangular shape.

[0023] Typically, the blade is made in one piece.

[0024] The present invention also relates to an assembly comprising a first blade according to the present invention and a second blade according to the present invention.

[0025] In such an assembly, the first blade and the second blade are typically identical, and the first lateral edge of the first blade is configured to cooperate by form complementarity with the second lateral edge of the first blade.

[0026] Typically, the first blade and the second blade are mounted circumferentially adjacent around the main axis.

[0027] The present invention also relates to a movable wheel comprising a plurality of blades according to the present invention, circumferentially assembled to the circumferentially adjacent blades of the plurality of blades.

[0028] Typically, the movable wheel comprises a disc having at its external periphery cells in which the blades are mounted. Typically, the blades are mounted by their respective feet.

[0029] The present invention also relates to a method of assembling a mobile wheel according to the present invention, comprising a step of applying a pre-torsion force to the first blade and positioning the first blade circumferentially adjacent to a second blade so as to bring the first bearing surface of one into contact with the second bearing surface of the other circumferentially adjacent blade.

[0030] The present invention also relates to a turbomachine comprising the moving wheel according to the present invention. Brief description of the drawings

[0031] The object of the present disclosure and its advantages will be better understood upon reading the detailed description given below of various exemplary embodiments given as non-limiting examples. This description refers to the appended pages of figures, in which:

[0032] [Fig-1] [Fig.l] represents a simplified and partial schematic view of a turbo aircraft fan engine in axial section;

[0033] [Fig.2] [Fig.2] represents a schematic sectional view of a turbojet blade according to one embodiment of the invention.

[0034] [Fig.3] [Fig.3] represents a schematic view of a blade according to a first embodiment, seen in section plane III of [Fig.2].

[0035] [Fig.4] [Fig.4] represents an assembly of two blades according to a first embodiment, seen in section plane III of [Fig.2].

[0036] [Fig.5A][Fig.5B] Figures 5A and 5B represent an assembly of two blades according to the first embodiment, respectively in close relative position and in distant relative position, according to an enlargement V of [Fig.4].

[0037] [Fig.6A][Fig.6B] Figures 6A and 6B represent an assembly of two blades according to a second embodiment, respectively in close relative position and in a distant relative position, according to the enlargement V of [Fig.4].

[0038] [Fig.7A][Fig.7B] Figures 7A and 7B represent an assembly of two blades according to a third embodiment, respectively in the close relative position and in the distant relative position according to the enlargement V of [Fig.4]. Description of the embodiments

[0039] [Fig. 1] shows an example of a mixed-flow turbojet engine 10 having a main axis A of rotation shown in phantom. The air flow in the turbojet engine 10 is shown in the diagram from left to right. The inlet of the turbojet engine 10 has a fan 11 driving the air inside the turbojet engine 10. The air flow is then divided into a primary air flow and a secondary air flow. The primary air flow is compressed successively by a low-pressure compressor 12 and a high-pressure compressor 13, driven respectively by a low-pressure turbine 16 and a high-pressure turbine 15. Between the compressors 12, 13 and the turbines 15, 16 is a combustion chamber 14 receiving the air compressed by the compressors 12, 13 and into which the fuel is injected in order to carry out combustion.The combustion gases exit the combustion chamber 14, driving the turbines 15 and 16, and join the secondary air flow at the outlet, the latter passing through the turbojet engine 10 on the radial periphery of the primary air flow. The combustion gases exiting the turbines 15, 16 are then ejected from the turbojet engine 10 through the nozzle 17, at the distal end of the turbojet engine 10.

[0040] Blade structures 30, and in particular blade heel 34, will be described below with reference to the view of [Fig. 2] and to the sectional views of FIGS. 3 to 7B.

[0041] The blade 30 will be described in an orthogonal reference frame formed of a first direction X, a second direction Y and a third direction Z, where the first direction X is a direction of rotation of the blade and where the second direction Y is a circumferential direction.

[0042] In particular, the blade 30 mounted in the low-pressure turbine 16 will be described, that is to say in which the first direction X is parallel to the main axis A, in which the second direction Y is a circumferential direction of the turbine 16, and in which the third direction Z is a radial direction of the blade.

[0043] Typically, the first direction X is oriented from upstream to downstream, so that in Figures 1 and 2, the upstream to downstream direction corresponds to a direction from left to right.

[0044] Typically, [Fig.2] is a schematic view of a blade 30 in section along an axial plane.

[0045] The blade 30 comprises a blade root 36 at a proximal or radially inner end and by which the blade 30 can be mounted on an inner casing (not re- presented), as well as a heel 34 at a distal or radially outer end.

[0046] The heel 34 is typically provided to face a casing 20, for example an abradable element 22 of the casing 20.

[0047] The blade 30 also comprises a vane 32, extending between the blade root 36 and the heel 34 and capable of exchanging mechanical power with the fluid.

[0048] The blade 30 typically comprises sealing lips 34a, for example two lips substantially aligned along the first direction X.

[0049] Typically, the wipers 34a are part of the heel 34 of the blade 30, and extend from a platform 34b of the heel 34.

[0050] The wipers 34a are mounted radially opposite the casing 20, in particular the abradable element 22 of the casing 20, so as to reduce the fluid leakage flow rate bypassing the blade 30 associated with a reduction in the mechanical power extracted from the fluid.

[0051] The heel 34 of the blade 30 may be formed in one piece. In particular, the blade 30 may be formed in one piece.

[0052] The wipers 34a extend in a substantially radial direction, that is to say a direction having a non-zero component in the third direction Z.

[0053] The platform 34b extends in a substantially radial plane.

[0054] The structure of the heel 34, and more particularly of the platform 34b, will be described in more detail relative to the section plane III of [Fig.2], corresponding to the mean plane of the platform 34b, that is to say the plane equidistant between the radially inner and outer faces of the platform 34b.

[0055] A first embodiment of the blade 30 will be described in detail with respect to FIGS. 3, 4, 5A and 5B.

[0056] For reasons of simplicity of representation, in the example of Figures 4, 5A and 5B, two identical blades 30 will be described rather than a single one in order to illustrate the blade retention mechanism. It is understood that the characteristics which will be defined relative to one or the other blade 30 may be the characteristics of a single blade 30 according to the invention.

[0057] In particular, a male part of a blade 30 and a female part of another blade 30 will be described, the blades 30 each carrying said male and female parts.

[0058] The heel 34 comprises a first circumferential end edge 40 and a second circumferential end edge 50.

[0059] The first circumferential end edge 40 and the second circumferential end edge 50 are provided to cooperate with each other by form complementarity, so as to be able to assemble. Typically, the first circumferential end edge 40 is a male circumferential end edge, provided to cooperate by form complementarity with the second circumferential end edge 50 of an adjacent dawn 34.

[0060] Such a complementarity of shape makes it possible to make the circumferentially adjacent blades 30 integral with one another.

[0061] For example, as shown in Figures 3 and 4, the first circumferential end edge 40 has an overall chevron shape including a flat ("Z" shape), making it possible to create contact zones in order to keep the blades 30 circumferentially aligned.

[0062] The first circumferential end edge 40 and the second circumferential end edge 50 respectively comprise a first bearing surface 44 and a second bearing surface 54, configured to be in contact with each other. The first bearing surface 44 and the second bearing surface 54 are typically in translational sliding contact.

[0063] Typically, the blades 30 are mounted relative to each other in pretorsion along their length direction, i.e. along the third direction Z, so that the circumferentially adjacent blades 30 bear against each other via their respective first bearing surface 44 and second bearing surface 54.

[0064] The first circumferential end edge 40 and the second circumferential end edge 50 respectively comprise a first retention member 42 and a second retention member 52, which will be described in more detail with respect to Figures 5A and 5B, representing an enlargement of the zone V of [Fig.4] comprising the lateral edges 40, 50 of two circumferentially adjacent blades 30.

[0065] [Fig.5A] represents the blades 30 in a position called “close position” or “close relative position”, and [Fig.5B] represents the blades 30 in a position called “far position” or “far relative position”, it being understood that the qualifiers “close” and “far” are understood relative to each other.

[0066] In the close relative position, in [Fig.5A], the circumferentially adjacent blades 30 bear against each other by their bearing surfaces 44, 54.

[0067] The torsional force, which tends to press the blades 30 against each other at the level of the bearing surfaces 44, 54, tends to constrain the relative movement of the blades 30 against each other to a translation in a direction t transverse to the bearing surfaces 44, 54 and included in the plane of the platforms 34b, substantially circumferential.

[0068] Generally, herein, “near”, “far” or any associated term means proximity or distance in the transverse direction t. In particular, “near” or “far” does not define the presence or absence of contact between the blades 30, it being understood that the blades 30 may be closer or further apart. from each other although in contact at their bearing surfaces 44, 54.

[0069] The first retention member 42 is typically a male retention member, for example projecting from the first bearing surface 44. The first retention member 42 has, for example, a crenellation shape.

[0070] The second retention member 52 is typically a female retention member, for example having the shape of a cavity capable of receiving the first retention member 42.

[0071] Typically, the relative dimensions of the first retention member 42 and the second retention member 52 are provided so that in a close relative position, the retention members 42, 52 are not in contact with each other.

[0072] Typically, the width of the second retention member 52 measured along the direction t is greater than the width of the first retention member 42 measured along the direction t.

[0073] Typically, the height of the second retention member 52 measured along the direction t is greater than the height of the first retention member 42 measured perpendicular to the direction t.

[0074] Such an arrangement allows a certain level of movement in the direction t. In particular, the blades 30 can move away from each other in a direction t up to the distant relative position.

[0075] In the distant relative position, the retention members 42, 52 come into contact with each other so as to prevent any further relative movement of the blades 30.

[0076] The remote relative position typically corresponds to an assembly position, i.e. to a relative configuration of two adjacent blades 30 during assembly. The contact between the retention members 42, 52 thus makes it possible to ensure that the blades are held in place two by two.

[0077] This support makes it possible in particular to facilitate assembly by reducing the risks of blades 30 becoming dislodged.

[0078] This maintenance also makes it possible to prevent poor relative positioning of the blades 30 relative to each other during operation of the turbomachine.

[0079] The close relative position typically corresponds to an operating position, i.e. a relative configuration of two circumferentially adjacent blades 30 during operation. The retention members 42, 52 are thus kept at a distance, thereby reducing the risks of degradation of the retention members 42, 52 as well as the risks of transmission of parasitic forces between the blades.

[0080] Typically, a lateral surface 42a of the first projecting retention member 42 comes to bear against a corresponding lateral surface 52a of the second member. retention 52.

[0081] The first retention member 42 extends forming an angle 01 with the first bearing surface 44, for example equal to 90°.

[0082] Typically, the angle 01 is measured between the lateral surface 42a and the bearing surface 44.

[0083] The second retention member 52 extends forming an angle 02 with the second bearing surface 54, for example equal to 90°.

[0084] Typically, the angle 02 is measured between the lateral surface 52a and the bearing surface 54.

[0085] Typically, angle 01 and angle 02 are equal.

[0086] Such orientations of lateral surfaces 42a, 52a of the retention members 42, 52 make it possible to prevent movement in the direction t.

[0087] The angles 01 and 02 may be acute angles, i.e. less than 90°. In this way, the reaction force normal to the surfaces tends to press the blades 30 against each other.

[0088] The blades 30 can then move relatively to each other between the near relative position and the far relative position. In particular, the blades 30 are constrained to move only between the near relative position and the far relative position.

[0089] For example, contact (not shown) between the first circumferential end edge 40 and the second circumferential end edge 50 may prevent movement beyond the near relative position.

[0090] The contact in close relative position may for example take place by contact between two or more surfaces of the side edges 40,50, for example by shape-matching insertion of the side edges 40,50 into each other.

[0091] The contact between the retaining members 42, 52 may prevent movement beyond the remote relative position, and in particular the contact between the lateral surfaces 42a, 52a of the retaining members 42, 52.

[0092] The displacement amplitude ô between the near relative position and the far relative position is measured in the direction t.

[0093] The lateral surfaces 42a, 52a being in contact in the distant relative position, the distance between the lateral surfaces 42a, 52a measured in the direction t in the close relative position is equal to the displacement amplitude ô, shown in [Fig.5A].

[0094] Typically, the retention members 42,52 are provided to only come into contact in the remote relative position.

[0095] Such a structure makes it possible in particular to reduce the risks of wear and damage to the retention members 42, 52, by any known mode of wear or damage, including abrasion, fatigue or brittle fracture.

[0096] Such a structure then makes it possible to ensure the functions of holding the blades 30 relative to each other, while allowing a certain clearance between the blades 30 and thus a certain level of tolerance.

[0097] For the purposes of illustration, the blades 30 have been described in a simplified translational displacement mode along rectilinear support surfaces 44, 54.

[0098] On the one hand, it is understood that the bearing surfaces 44, 54 are not necessarily rectilinear, in which case the contact between the bearing surfaces 44, 54 is not surface (or linear seen in the plane V) but linear (or point seen in the plane V). In such a case, the direction t is curvilinear and the displacement amplitude ô is measured along the curvilinear direction t.

[0099] On the other hand, it is understood that the distance between the blades 30 is not restricted only when the bearing surfaces 44, 54 are in surface contact.

[0100] For example, twisting of the blades may result in a small angle being formed between the bearing surfaces 44, 54.

[0101] Due to the height of the retention members 42, 52, the obstacle function at a greater distance can still be ensured despite imperfect contact between the members 42, 52.

[0102] The first retention member 42 and the second retention member 52 may have a rectangular shape. Typically, the second retention member 52 has a rectangular notch shape corresponding to the shape of the first retention member 42.

[0103] A second embodiment will be described with respect to Figures 6A and 6B, and a third embodiment will be described with respect to Figures 7A and 7B.

[0104] [Fig.6A] represents blades 30 according to a second embodiment in a close relative position, and [Fig.6B] represents blades 30 according to a second embodiment in a distant relative position.

[0105] [Fig.7A] represents blades 30 according to a third embodiment in a close relative position, and [Fig.7B] represents blades 30 according to a third embodiment in a distant relative position.

[0106] Elements common to the first, second and third embodiments will not be described again, and identical or similar members will be designated by numerical references incremented by 100 or 200.

[0107] The second and third embodiments differ from the first embodiment in the shape of the respective first retention members 152,252 and the respective second retention members 242,252.

[0108] As shown in Figures 6A and 6B, the first retention member 142 may have a triangular shape, a first surface of which is the lateral surface 142a and a second surface of which is slightly inclined relative to the bearing surface 142.

[0109] The second retention member 152 can then have a shape corresponding to the shape of the first retention member 142, i.e. a corresponding triangular notch shape.

[0110] As shown in Figures 7A and 7B, the first retention member 242 may be step-shaped.

[0111] The second retention member 152 can then have a shape corresponding to the shape of the first retention member 142, that is to say a step shape, for example a step of greater height.

[0112] Such structures make it possible, for example, to increase the mechanical resistance of the retention members, in particular of the first retention member 142, 242.

[0113] For example, such structures make it possible to reduce the stress concentration due to the support between the first and second retention members.

[0114] Two blades 30 thus formed can be mounted circumferentially against each other so as to form an assembly.

[0115] For example, a pre-torsion force may be applied to one of the blades 30 before positioning it circumferentially adjacent to the other of the blades 30 so as to bring their respective bearing surfaces 44, 54, 144, 154, 244, 254 into contact.

[0116] In particular, a plurality of blades 30 thus formed may be circumferentially assembled to each of the circumferentially adjacent blades 30 of the plurality of blades 30 so as to form a moving wheel.

[0117] A pre-torsion force may then be applied to each of the blades 30 of the plurality of blades 30 before positioning it circumferentially adjacent to another blade 30.

[0118] Although the present invention has been described with reference to specific embodiments, it is obvious that modifications and changes may be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various illustrated / mentioned embodiments may be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

[0119] Typically, the above embodiments have been described in the case where the first circumferential end edge 40 is a male circumferential end edge, the first retaining member 42 is a male member, the second circumferential end edge 50 is a female circumferential end edge and the second retaining member 52 is a female member.

[0120] It is understood that any male / female combination is possible among the four combinations: first circumferential end edge 40 male or female and second circumferential end edge 50 corresponding among male or female, first retention member 42 male or female and second retention member 52 corresponding among male or female.

Claims

Claims

1. A turbomachine blade (30) intended to be mounted around a main axis (A) of rotation of the turbomachine and having at its distal end a heel (34) comprising a first circumferential end edge (40) and a second circumferential end edge (50) respectively configured to cooperate by form complementarity with the second circumferential end edge (50) and the first circumferential end edge (40) of the heel (34) of another blade circumferentially adjacent and identical to said blade (30), in which the first circumferential end edge (40) comprises a first bearing surface (44) and a first retention member (42), the second circumferential end edge (50) comprises a second bearing surface (54) and a second retention member (52),the first retention member (42) and the second retention member (52) respectively comprising a complementary male retention member and a complementary female retention member, the first circumferential end edge (40) of said blade (30) and the second circumferential end edge (50) of the other circumferentially adjacent blade being configured to define a translational sliding contact between the first (44) and second (54) bearing surfaces when said circumferentially adjacent blades move relative to each other between a close relative position and a distant relative position, and wherein the first retention member (42) of said blade (30) and the second retention member (52) of the other circumferentially adjacent blade are configured to be spaced apart in the close relative position and to come into contact in the distant relative position.,

2. A blade according to claim 1, wherein the first retaining member (42) and the second retaining member (52) of the circumferentially adjacent blades are configured to contact only in the distant relative position.

3. A blade according to claim 1 or 2, wherein the transition from the near relative position to the far relative position is achieved by circumferential relative movement of the heels (34) around the main axis (A).

4. A blade according to any one of claims 1 to 3, wherein the first bearing surface (44) comprises a cavity capable of receiving the second retention member (52).

5. A blade according to any one of claims 1 to 4, wherein at least one of the first retaining member (42) and the second retaining member (52) has a triangular or rectangular shape.

6. Blade according to any one of claims 1 to 5, made in one piece.

7. An assembly comprising a first blade according to any one of claims 1 to 6 and a second blade according to any one of claims 1 to 6, the first and second blades being mounted circumferentially adjacent around the main axis (A).

8. A movable wheel comprising a plurality of blades according to any one of claims 1 to 6, circumferentially joined to circumferentially adjacent blades of the plurality of blades.

9. A method of assembling a moving wheel according to claim 8, comprising a step of applying a pre-torsion force to a first blade and positioning the first blade circumferentially adjacent to a second blade so as to bring the first bearing surface (44) of one into contact with the second bearing surface (54) of the other circumferentially adjacent blade.

10. A turbomachine comprising a moving wheel according to claim 8.

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